目标邮编密码 &CRC [英] Objective Zip Password & CRC

问题描述

我正在使用 Objective Zip 压缩我的 iOS 应用上的一些文件.

I'm using Objective Zip to zip-up some files on my iOS app.

我想用密码保护他们并记下电话...

I want to protect them with a password and note the call...

- (ZipWriteStream *) writeFileInZipWithName:(NSString *)fileNameInZip fileDate:(NSDate *)fileDate compressionLevel:(ZipCompressionLevel)compressionLevel password:(NSString *)password crc32:(NSUInteger)crc32;

...需要一个 CRC32 值.

...requires a CRC32 value.

不是这方面的专家，并且在维基百科等上阅读了关于 CRC 的内容，我仍然不确定在此处输入什么值.

Not being expert on this, and having read-up about CRC on wikipedia etc., I'm still not sure what value to enter here.

可以为零吗?它应该是文件的字节数吗?任何随机数?

Can it be zero? Should it be the byte-count of the file? Any random number?

感谢帮助和指导.

谢谢

推荐答案

首先，您必须计算要压缩的文件的 CRC 值:

At first you have to calculate the CRC value for your file you want to zip:

NSData *data = [[NSData alloc] initWithContentsOfFile:@"/path/to/your/file/to/zip"];
unsigned long result = crc32(0, data.bytes, (unsigned int)data.length);

创建一个新的 Zip，添加您的文件并传递 CRC 结果:

Create a new Zip, add your file and pass the CRC result:

ZipFile *zipFile= [[ZipFile alloc] initWithFileName:@"/tmp/File.zip" mode:ZipFileModeCreate];
ZipWriteStream *stream= [zipFile writeFileInZipWithName:@"File.name" fileDate:[NSDate date] compressionLevel:ZipCompressionLevelDefault password:@"your_password"] crc32:result];
[stream writeData:data];
[stream finishedWriting];

[zipFile close];

确保 zip.c (MiniZip) 中的以下行未被注释:

Be sure that you the following line in zip.c (MiniZip) is uncommented:

//#define NOCRYPT

还要检查您是否已将文件 crypt.h 添加到您的项目中.

Also check that you have added the file crypt.h to your project.

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